Phytosociology of native forests understock and PRAD under mining influence, Paragominas, Pará, Brazil

Abstract

The Degraded Area Recovery Programs (PRAD), established by large companies that alter and degrade the landscape for its implementation and operation, aim to restore vegetation and its processes and ecological services. Mining is increasingly present in the Amazon biome, which can suffer irreversible losses of biodiversity if not properly managed. This research aimed to analyze the floristic and structural composition of the understory in areas of Native Forest (FN) and in PRAD areas in the HYDRO mining, municipality of Paragominas, Pará, relating the phytosociological parameters with the morphological and ecological atributes in areas with 6 years of regeneration. Eighteen plots measuring 40 x 250 m were used (9 in the PRAD and 9 in the FN) and all individuals with CAP≥30 cm were sampled. To compare the richness and abundance of the two areas, the Bray Curtis analysis was performed. Seventy-four genera, 110 species and a total of 43 families were sampled, nine of which were present together in the FN and PRAD areas, and four (Asteraceae, Hypericaceae, Malpighiaceae and Solanaceae) were found only in PRADs. Only the species Jacaranda copaia was sampled in both environments.  The Bray-Curtis analysis and the grouping by means of groups showed the floristic (richness) and structural (abundance) separation of the two analyzed environments (FN and PRAD), with a dissimilarity around 95%. The areas sampled within Hydro's property have high species richness, especially forest areas, where there is no direct interference from the bauxite extraction process. The PRAD areas presented species normally found in areas with higher incidence of solar radiation and more altered, since they are areas that have only eight years since the beginning of the restoration process. We did not find floristic similarity between the two environments studied, a result already expected, based on the differences of regeneration states. We hope that over time these differences will decrease, which will lead us to believe that forest succession is taking place in a way that guarantees that the physiognomy and dynamics of the vegetation is restored, as well as its ecosystem services.